Ellipsograph



- 2 Sheets-$heet in E.- G. CHORMANN.

Ellipsograp'h. No. 22,347. Patented Dec. 21', 1858.

Wu-Hens Phoko-Likhugnphar, Washington. D. c.

2 Sheets$heet 2.; E. G. CHORMANN Ellipsograph. No. 22,347. Patented Dec 21, 1 5

UNITED STATES PATENT OFFICE.

E. G. CHORMANN, OF PHILADELPHIA, PENNSYLVANIA.

ELLIPSOGRAPH.

Specification of Letters Patent No. 22,347, dated December 21, 1858.

To all whom it may concern:

Be it known that I, E. G. CHOIUIANN, of Philadelphia, county of Philadelphia, in the State of Pennsylvania, have invented a new and useful Machine for Drawing Ellipses; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon.

The nature of my invention consists in a new and useful machine for drawing ellipses as hereinafter fully described. t

In the accompanying drawing Figure 1, represents a perspective view of my machine. Fig. 2, represents a front elevation with holder arm thrown up. Fig. 3, represents a vertical longitudinal section through the center and, Fig. 4, detail bottom view of beam and slotted plate; similar letters denoting the same parts in different views.

A, represents a post or rod which is secured to a suitable base, C, and upon which slides, and is secured by an adjustable thumb screw, a, a sliding stand, B, which has a projecting arm, B. To said arm B, is hinged by the pivot, 19, another arm, D, through the extremity of which passes a stud, F, furnished at its lower end with a disk or face plate, G; in the under face of said disk are formed two slots, m, (see Figs. 2 and l) bisecting in each other in which slide freely the two rectangular shoes, 2', i; said shoes are made in two parts pivoted together so that each can turn horizontally around a common axis and one of which, '2', has its lower half securely fastened in the beam, I, (in the position seen at Fig. 3,) the other, i, fitting loosely in a slot formed in said beam, and having through it a hole or female screw to accommodate the screw shaft, d, which shaft takes its bearing at one end, in the stationary half of shoe, 2', and at the other in the end of beam, I, said shaft, cl, is furnished with a suitable head, (Z, by which it may be readily turned (for purposes to be described), on either side of the beam, I, is bolted a semi-elliptical plate, II, which bears equally at all points upon the under surface of the disk, Gr, and thus keeps the beam, 1, always in the same horizontal plane.

f, is a sliding carriage which moves freely in a slot in the under side of beam, I, and is adjusted along the length of the beam by means of a screw shaft, a, passing through it, (said screw shaft being furnished with a suitable head, 0'.) From the under side of the carriage, f, projects downward a hollow stand or leg, J, in which may be secured, by a set screw, is, a pencil, e.

E, is a semicircular plate having formed in it a curved slot, 1), concentric with the pin, 7); said slot is to accommodate athumb screw, a, which projects through it from the arm, D, and by which said arm, D, is retained at any point in its arc of motion, for instance in an extremely elevated position as illustrated at Fig. 2.

The operation of my improved ellipsograph is as follows: The several parts being constructed, and relatively arranged as described, and shown in the drawings, by simply swinging the beam, I, around in a horizontal plane, the pencil point, e, is caused to describe an ellipsis, by virtue of the pivot shoes, i, 2", sliding in the slots, m, in the face plate, G, on the principle of the Scotch trammel, which is well understood; the size of the figure described is varied by turning the screw shaft, 0, by its head, 0, whereby the carriage, f, carrying the pencil is moved farther from or nearer to the centers of motion. The proportions of the figure, or relative lengths of the axes, are varied, by turning the screw shaft (1, (by its head, d,) which causes the movable shoe, 2', to approach towardor recede from the stationary shoe, 2', and thus change the centers or foci of the figure to any points required; it will then be understood that by turning the screw rods, 0, and, d, the size and proportions of the figure described by the pencil point may be varied at pleasure.

The shoes, 1', i, it will be seen are made to extend along in their respective slots, a distance greater than the width of said slots, so that as each shoe passes backward and for ward in its respective slot its motion is not at all interrupted by passing across the other slot, (see diagram).

The object of having the double adjustment formed by the raising and lowering of the stand, B, on post, A, and the vibration of arm, 1), around the pin, 2, is, that the figures may be readily drawn on surfaces lying in different planes and is particularly obvious when the instrument is used by the lithographer or engraver who simply substitutes for the pencil c, a dry point or graver, and draws directly upon the stone or block, which varying in thickness require an adjustment of the point, e, to very different planes of motion horizontally, and not always having the top and bottom surfaces parallel, require the point, 0, often to move in a plane lying at an angle with the base of the apparatus.

The obvious advantages of my improved instrument areits universal adjustment to draw the figure in different relative'planes with the base, on which rest the object to be drawn upon; the simplicity of thecombination embracing an adjustment to vary the size and also proportions of the figureand the perfection of the motion of the point; in consequence of the shoes, 2', i, being made of such length as to pass the slots without swerving from their line.

Having fully described the construction and operation of my improved instrument, and disclaiming the broad feature of changing the relative position of the shoes or pins which run in the slots of the plate, or the changing of the distance of the pencil or gra-ver carrier from the foci, what I do claim and desire to secure by Letters Patent is:

1. Constructing the shoes, 2', and, i, in two parts swiveled together as specified, in combination with the adjusting screw shaft, d, the whole arranged and operating as described.

2. In combination with the screw adjustment of the movable shoe, the arrangement of the pencil or dry point carrier, f, on-a screw shaft, 0, in order that the relative lengths of the axes may be readily varied to the smallest extent, or a series of concentric ellipses be drawn varying very slightly in size.

3. Arranging the drawing apparatus with a vibrating adjustable arm, D, on a vertically adjustable arm, B, as herein described for the purpose set forth.

E. G. CHORMANN.

lVitnesses SAMPSON VVALLIs, N. B. KNEAss. 

